Co-current Rotary Dryers vs Counter Current Rotary Dryers In co-current rotary dryers, the heated drying air flows in the same direction as the product, and in counter current rotary models the drying airflow travels against the flow of the product. These rotary dryers directly expose the product to hot air produced by the heat source. As the drum rotates, lifting "flights" mounted on the inside of the drum shell tumble, slide, lift and shower the material into the air stream. Lifting flights are carefully designed to accommodate the material being dried and ensure the product is uniformly exposed. This agitation ultimately leads to higher efficiencies and reduces processing times compared to stationary units. It is not uncommon for a process taking 1 hour in a stationary furnace to take just a few minutes in a rotary dryer. A number of options for types of drying fuel and control methods are available including stand-alone microprocessor controllers or PLC controllers that directly interface with plant control systems.
